Part-forming machine having an in-mold integrated vision system and method therefor

ABSTRACT

A part-forming machine having an in-mold integrated vision system and method therefor for verifying the presence, absence and quality of molded parts therein. The image of the mold and/or part is acquired at a substantially parallel angle relative to the image-capturing source thereby allowing the imaging of the mold while the mold is opening thus increasing the resolution, speed and accuracy of part-forming machine imaging systems.

TECHNICAL FIELD

[0001] The present invention relates generally to part-forming machines,and more specifically to a part-forming machine having an in-moldintegrated vision system and a method therefor.

BACKGROUND OF THE INVENTION

[0002] The parts forming industry is one of the world's largestindustries in both total revenue and employment. As a multibilliondollar industry, even small improvements to the manufacturing processcan prove to have an enormous efficiency and thus financial impact.Numerous methods and machines have been designed for forming parts. Forinstance, parts are generally formed via molds, dies and/or by thermalshaping, wherein the use of molds is presently the most widely utilized.There are many methods of forming a part via a mold, such as, forexemplary purposes only, stretch-blow molding, extrusion blow molding,injection blow molding, vacuum molding, rotary molding and injectionmolding.

[0003] One typical method of forming hollow containers is via a widelyutilized process known as stretch blow-molding, wherein typically athree piece mold having two opposing side members and a bottom/push-upmold is utilized. Commonly, an injection molded preform, shapedgenerally like a test tube (also known as the parison), is inserted intothe top of the mold. A rod is inserted inside the parison and isutilized to extend the parison to the bottom of the mold, upon whichcompressed air is forced into the parison, thus stretching the parisonoutward first toward the approximate center of the side mold members andthen over and around the push-up/bottom mold. The parison is generallyamorphous prior to initiating the blow process; however, afterstretching the parison, the molecules align thereby forming a containerhaving high tensile strength.

[0004] An even more popular method is the forming of parts utilizing atechnique known as injection molding. Injection molding systems aretypically used for molding plastic and some metal parts by forcingliquid or molten plastic materials or powdered metal in a plastic bindermatrix into specially shaped cavities in molds where the plastic orplastic binder matrix is cooled and cured to make a solid part. Forpurposes of convenience, references herein to plastic and plasticinjection molds are understood to also apply to powdered metal injectionmolding and other materials from which shaped parts are made byinjection molding, even if they are not mentioned or describedspecifically.

[0005] A typical injection mold is made in two separable portions ormold halves that are configured to form a desired interior mold cavityor plurality of cavities when the two mold halves are mated orpositioned together. Then, after liquid or molten plastic is injectedinto the mold to fill the interior mold cavity or cavities and allowedto cool or cure to harden into a hard plastic part or several parts,depending on the number of cavities, the two mold halves are separatedto expose the hard plastic part or parts so that the part or parts canbe removed from the interior mold cavity or cavities.

[0006] In many automated injection molding systems, ejector apparatusare provided to dislodge and push the hard plastic parts out of the moldcavities. A typical ejector apparatus includes one or more elongatedejector rods extending through a mold half into the cavity or cavitiesand an actuator connected to the rod or rods for sliding or strokingthem longitudinally into the cavity or cavities to push the hard plasticpart or parts out of the cavity or cavities. However, other kinds ofejector apparatus, such as robotic arms, scrapers, or other devices mayalso be used. Such ejectors are usually quite effective for dislodgingand pushing hard plastic parts out of mold cavities, but they are notfoolproof. It is not unusual for an occasional hard plastic part tostick or hang-up in a mold cavity in spite of an actuated ejector. Onequite common technique is to design and set the ejectors to actuate orstroke multiple times in rapid succession, such as four or five cycleseach time a hard plastic part is to be removed, so that if a part sticksor is not removed from a mold cavity the first time it is pushed by anejector, perhaps it can be dislodged by one or more subsequent hits orpushes from the ejectors. Such multiple ejector cycles are ofteneffective to dislodge and clear the hard molded plastic parts from themolds. Disadvantages of multiple ejector cycling, however, include theadditional time required for the multiple ejector cycling each time themold is opened to eject a hardened plastic part before it is closed forinjection of a subsequent part and the additional wear and tear on theejector equipment and the molds occasioned by such multiple cycling.Over the course of days, weeks, and months of injection molding parts inrepetitive, high volume production line operations, such additionaltime, wear, and tear can be significant production quantity and costfactors.

[0007] On the other hand, stuck or incompletely ejected hard plasticparts can also cause substantial damage to molds and lost productiontime. In most injection mold production lines, the injection moldingmachines operate automatically, once the desired mold is installed, incontinuous repetitive cycles of closing the mold halves together,heating them, injecting liquid or molten plastic into the mold cavities,cooling to cure or harden the plastic in the mold into hard plasticparts, opening or separating the mold halves, ejecting the molded hardplastic parts, and closing the mold halves together again to moldanother part or set of parts. Very high injection pressures are requiredto inject the liquid or molten plastic into the mold cavities tocompletely fill all portions of the cavities in a timely manner, andsuch high pressures tend to push the mold halves apart during injectionof the plastic. To prevent such separation of the mold halves duringplastic injection, most injection molding machines have very powerfulmechanical or hydraulic rams to push and hold the mold halves together.If a hard plastic part from the previous cycle is not ejected andcompletely removed from between the mold halves, the powerful mechanicalor hydraulic rams will try to close the mold halves onto the hardplastic part, which can and often does damage one or both of the moldhalves. Molds are usually machined very precisely from stainless steelor other hard metal, so they are very expensive to replace, and thedowntime required to change them is also costly in labor and lostproduction. It is also not unusual for some of the plastic in a moldcavity to break apart from the rest of the part being molded in thecavity and remain in the mold cavity when the rest of the molded part isejected. Such remaining material will prevent proper filling and moldingof subsequent parts in the cavity, thus causing the subsequent moldedparts to be defective. In automated production lines, substantialnumbers of such defective parts can be produced before someone detectsthem and shuts down the injection molding machine for correction of theproblem.

[0008] To avoid such mold damage, down-time, and defective molded partsas described above, various technologies have also been developed andused to sense or determine whether the hard molded plastic parts haveindeed been dislodged and completely ejected or removed from the moldsbefore the mechanical or hydraulic rams are allowed to close. Suchtechnologies have included light beam sensors, vision systems, airpressure sensors, vacuum sensors, and others. U.S. Pat. No. 4,841,364issued to Kosaka et al. is exemplary of a vision system in which videocameras connected to a vision system controller take video images of theopen mold halves for computerized comparison to video images of theempty mold halves stored in memory to detect any unremoved plastic partsor residual plastic material in the mold halves. U.S. Pat. No. 4,236,181issued to Shibata et al. is also an example of a vision system whereinphotosensors are provided on a face plate of a CRT to electricallydetect if a part has been removed.

[0009] As an improvement to the above systems, U.S. Pat. No. 5,928,578issued to Kachnic et al. provides a skip-eject system for an injectionmolding machine, wherein the system comprises a vision system foracquiring an actual image of an open mold after a part ejector hasoperated and a controller for comparing such actual image with an idealimage of the open mold to determine if the part still remains in themold. If so, the controller outputs an ejector signal to actuate theejector to cycle again. Additionally, the patents to Kachnic et al.,Kosaka et al. and Shibata et al. provide a means for inspecting the partfor defects.

[0010] However, in view of the present system and method, the priorsystems are disadvantageous. More specifically, the above systems havetypically utilized charge coupled device (CCD) cameras positioned on thetop or sides of the mold to acquire an image of the mold. This requiresthat the mold be completely opened before an image can be acquired, thusslowing down the inspection process. Moreover, due to the angle of thesensing device relative to the mold, a skewed image is acquired therebyresulting in decreased resolution of the image and increased inspectionerror.

[0011] Therefore, it is readily apparent that there is a need for apart-forming machine having an in-mold integrated vision sensor andmethod therefor that provides an image that is acquired at a relativelyparallel angle from the sensor and thus provides more accurate detectionresolution. It is, therefore, to the provision of such an improvementthat the present invention is directed.

SUMMARY OF THE INVENTION

[0012] According to its major aspects and broadly stated, the presentinvention is a part-forming machine having an in-mold integrated visionsensor and method therefor for verifying the presence, absence andquality of molded parts therein.

[0013] Thus, a feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles and determines the presence, absence and/orquality of the molded part.

[0014] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles thereby eliminating angled views and thusincreasing the resolution of the images by reducing the view area ofeach pixel.

[0015] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles and reduces the number of false rejectionsand/or false confirmations found in prior systems.

[0016] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles and thereby increases the accuracy of visioninspection systems thus increasing the efficiency of the part-formingprocess.

[0017] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles, thus increasing image resolution and therebyallowing the vision system to analyze a tighter tolerance in variationsin the process, resulting in an improved vision system and moldingprocess.

[0018] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles and provides a lighting source that isapplied at relatively parallel angles thus increasing illuminationconsistency and thereby allowing clearer image acquisition.

[0019] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles thereby allowing the image to be acquiredprior to the complete opening of the mold, thus increasing the speed ofthe machine.

[0020] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles, wherein coherent fiber optic bundles orcables are utilized to transfer the image to a sensor.

[0021] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles, wherein an illumination source illuminatesthe mold and/or part via a fiber optic cable or bundle.

[0022] Another feature and advantage of the present invention is toprovide a new and improved part-forming machine having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles thereby allowing the images to be acquiredprior to the complete opening of the mold and further allowing parts tobe ejected during the opening process and images acquired immediatelythereafter.

[0023] Another feature and advantage of the present invention is toprovide a new and improved part-forming machining having an in-moldintegrated vision sensor that captures images of the mold and/or part atrelatively parallel angles thus allowing the sensing device to morequickly focus on the image than in an angled view.

[0024] Another feature and advantage of the present invention is toprovide a new and improved method for verifying the presence, absenceand quality of molded parts in a part-forming machine wherein thepart-forming machine utilizes an in-mold sensor to acquire images of themold and/or part at relatively parallel angles thereto.

[0025] Another feature and advantage of the present invention is toprovide a new and improved method for verifying the presence, absenceand quality of molded parts in a part-forming machine, wherein thepart-forming machine utilizes an in-mold sensor, and wherein the processis more efficient and accurate over prior-art methods.

[0026] Another feature and advantage of the present invention is toprovide a new and improved method for verifying the presence, absenceand quality of molded parts in a part-forming machine, wherein thepart-forming machine utilizes an in-mold sensor thus allowing images tobe acquired during the mold-opening process.

[0027] Another feature and advantage of the present invention is toprovide a new and improved method for verifying the presence, absenceand quality of molded parts in a part-forming machine, wherein thepart-forming machine utilizes an in-mold sensor to acquire images atrelatively parallel positions thus allowing quicker focus or sensing ofthe part and/or mold.

[0028] These and other objects, features and advantages of the inventionwill become more apparent to one skilled in the art from the followingdescription and claims when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be better understood by reading theDetailed Description of the Preferred and Alternate Embodiments withreference to the accompanying drawing figures, in which like referencenumerals denote similar structure and refer to like elements throughout,and in which:

[0030]FIG. 1 is a perspective view of a typical prior-art injectionmolding machine equipped with a vision detection system positioned onthe top of the mold;

[0031]FIG. 2 is a partial cross-sectional side elevation view of theinjection molding machine of FIG. 1 showing the ejectors retracted;

[0032]FIG. 3 is a partial cross-sectional side elevation view of theinjection molding machine of FIG. 1 showing the ejectors extended;

[0033]FIG. 4 is a diagrammatic representation of the flow logic of aprior art system known as the skip-eject system;

[0034]FIG. 5 is a functional block diagram of a control of a prior-artsystem known as the skip-eject system;

[0035]FIG. 6 is a functional block diagram of a prior-art machinecontroller and analyzing means.

[0036]FIG. 7 is a partial perspective view of the present inventionshown in a preferred embodiment.

[0037]FIG. 8 is a functional block diagram of a control of the machinecontroller and analyzing means according to the present invention shownin a preferred embodiment.

[0038]FIG. 9 is a plane view of a representative pixel grid area of aprior-art vision system showing the effects of a skewed view on pixelarea.

[0039]FIG. 10 is a plane view of a representative pixel grid area of thepresent invention showing the reduced view area of each pixel.

DETAILED DESCRIPTION OF THE PREFERRED AND ALTERNATE EMBODIMENTS

[0040] In describing the preferred embodiment of the present inventionillustrated in the figures, specific terminology is employed for thesake of clarity. The invention, however, is not intended to be limitedto the specific terminology so selected, and it is to be understood thateach specific element includes all technical equivalents that operate ina similar manner to accomplish similar functions.

[0041] With regard to all such embodiments as may be herein describedand contemplated, it will be appreciated that optional features,including, but not limited to, aesthetically pleasing coloration andsurface design, and labeling and brand marking, may be provided inassociation with the present invention, all without departing from thescope of the invention.

[0042] To better understand the present system and method of thisinvention, a rudimentary knowledge of a typical prior-art injectionmolding machine and process is helpful. Therefore, referring first toFIGS. 1-3, a conventional automated injection molding machine 10 isshown equipped with a mold 12 comprising two mold halves 14, 16, asliding rod-type ejector system 18, and camera 20 for acquiring visualimages of the open mold half 14 in electronic format that can bedigitized, stored in memory, and processed to detect presence or absenceof a plastic part or material in the mold half 14.

[0043] In general, the exemplary conventional injection molding machine10 comprises two platens 24, 26 mounted on a frame made of fourelongated, quite substantial frame rods 28, 30, 32, 34 for mounting thetwo halves 14, 16 of mold 12. The stationary platen 24 is immovablyattached to rods 28, 30, 32, 34, while the moveable platen 26 isslidably mounted on the rods 28, 30, 32, 34 so that it can be moved backand forth, as indicated by arrow 36, in relation to the stationaryplaten 24. Therefore, the mold half 16 mounted on moveable platen 26 isalso moveable as indicated by arrow 36 in relation to the other moldhalf 14 that is mounted on stationary platen 24. A large hydraulic ormechanical ram 38, which is capable of exerting a substantial axialforce, is connected to the moveable platen 26 for moving the mold half16 into contact with mold half 14 and holding them together very tightlywhile liquid or molten plastic 40 is injected into mold 12, as best seenin FIG. 2. Most molds 12 also include internal ducts 15, 17 forcirculating heating and cooling fluid, such as hot and cold water,through the respective mold halves 14, 16. Cooling fluid supply hoses19, 21 connect the respective ducts 15, 17 to fluid source and pumpingsystems (not shown). Hot fluid is usually circulated through ducts 15,17 to keep the mold 12 hot during the injection of liquid or moltenplastic 40 into cavity 50. Then cold fluid is circulated through ducts15, 17 to cool the mold 12 to allow the liquid or molten plastic 40 tosolidify into the hard plastic part 22 that is shown in FIG. 3. Atypical plastic injector or extrusion system 42 may comprise an injectortube 44 with an auger 45 in the tube 44 for forcing the liquid or moltenplastic 40 through an aperture 46 in the stationary platen 24 andthrough a duct 48 in mold half 14 into a mold cavity 50 that is machinedor otherwise formed in mold half 16. In many applications, there aremore cavities than one in the mold 12 for molding cycle. In suchmultiple cavity molds, multiple ejectors may be required to eject thehard molded parts from all of the cavities. The plastic extrusion system42 also includes a hopper or funnel 52 for filling the tube 44 with thegranular solid plastic 41, a heating coil 47 or other heating systemdisposed around the tube 44 for heating the granular plastic 41 enoughto melt it in the tube 44 to liquid or molten plastic 40, and a motor 54for driving the auger 46.

[0044] After the liquid or molten plastic 40 is injected into the mold12 to fill the mold cavity 50, as illustrated in FIG. 2, and after theplastic 40 in the mold cavity has solidified as described above, the ram38 is actuated to pull the mold half 16 away from the mold half 14 sothat the hard plastic part 22 can be ejected from mold cavity 50. Oncethe mold halves 14, 16 are completely separated, the part-formingmachine controller 72 sends a signal to the camera 20 to acquire a firstimage of the mold half 16, wherein the image is analyzed to ensure thepresence of the part 22 in the mold half 16. Ejection of the hardplastic part 22, as mentioned above, can be accomplished by a variety ofmechanisms or processes that can be made more efficient and effective bythis invention, and the ejector system 18 illustrated in FIGS. 1-3 isbut one example that is convenient for describing this invention. Theejector system 18 includes two slidable ejector rods 56, 58 that extendthrough the moveable platen 26 and through mold half 16 into mold cavity50. When the mold 12 is closed for filling the mold cavity 50 withplastic 40, as shown in FIG. 2, the ejector rods 56, 58 extend to, butnot into the mold cavity. However, when the mold 12 is opened, as shownin FIG. 3, an ejector actuator 60, which comprises two small hydrauliccylinders 62, 66 and a cross bar 68 connected to the ejector rods 56,58, pushes the ejector rods 56, 58 into the mold cavity 50 to hit anddislodge the hard plastic part 22 and push it out of the cavity 50.Because one hit or push by the ejector rods 56, 58 is occasionally notenough to dislodge and push the hard plastic part 22 all the way out ofthe cavity 50, it is a common practice to cycle the ejector actuator 60several times to cause the ejector rods 56, 58 to reciprocate into andout of the cavity 50 repetitively so that, if the hard plastic part 22is still in the cavity, it will get hit and pushed several times, thusreducing instances when the hard plastic part 22 does not get completelyejected to a minimum. Next the part-forming machine controller 72 sendsa signal to the camera 20 to acquire an image of the mold half 16,including the cavity 50, and then the image is sent in electronic formto an image processing system, where it is digitized and compared by acomputer or microprocessor to an ideal image of the mold half 16 andempty mold cavity 50. If the image comparison shows that the mold cavity50 is empty and that the hard plastic part 22 has been cleared from themold half 16, the ram 38 is actuated to close the mold 12 to start a newmolding cycle. On the other hand, if the image comparison shows that thehard plastic part 22 has not been dislodged from the cavity 50 orcleared from the mold half 16, then the ram 38 is not allowed to closethe mold 12, and a signal is generated to notify an operator to checkthe mold, clear any residual plastic or the hard plastic part 22 fromthe cavity 50 and mold 12, and then restart the plastic injectionmolding machine 10.

[0045] As discussed above, the repetitive cycling of the ejector rods56, 58 that is practiced in some conventional injection molding systemsreduces occurrences of the hard plastic part 22 not being dislodged fromthe cavity 50 and removed from the mold half 16. However, for the manyinstances when one hit or push by the ejector rods 56, 58 would besufficient to dislodge and remove the hard plastic part 22, which faroutnumber the instances when additional hits or pushes by the ejectorrods 56, 58 are necessary, the repetitive cycling of the ejector system18 every time the mold 12 is opened also takes unnecessary time andcauses unnecessary wear and tear on the ejector system 18 and mold 12.As an improvement, a skip-eject system, as found in U.S. Pat. No.5,928,578 to Kachnic et al., is typically utilized, wherein the ejectorsystem 18 is actuated only when necessary. For instance, instead ofusing a large, fixed number of ejector rod 56, 58 strokes or cycles forevery time the mold 12 is opened in plastic part molding cycles, avariable number of ejector rod 56, 58 strokes is used to match eachmolding cycles ejection needs. The repetition of stroke cycles isdependent on the image of the mold 12 as obtained via the camera 20.

[0046] In the preferred embodiment of the present invention, as shown inFIGS. 7-8, sensoring system 300 comprises an image capture source 310, alinking member 320, a sensor device 330 and a analyzing means 340,wherein the analyzing means 340 is preferably a computer ormicroprocessor. Image capture source 310 is positioned preferably at thecenter of mold half 14 facing to the surface of mold half 16 such thatmold half 16 and any parts therein are generally at an approximatelyparallel angle relative to the image capture source 310. However, itshould be noted that in alternate embodiments image capture source 310may be positioned at various locations within the mold such that variousparts or specific areas of parts may be imaged at a substantiallyparallel angle. It is also contemplated that any number of image capturesources 310 may be positioned at various positions within the mold toincrease resolution and/or to improve the image analysis process. Imagecapture source 310 is, preferably, a coherent fiber optic bundle,wherein light waves and/or radiation can be captured thereby and allowedto travel therethrough to sensor device 330 via linking member 320.Linking member 320 is also preferably coherent fiber optic bundles. Thecoherent fiber optic bundles allow the image of the mold half 16 and/orpart 22 to be viewed remotely by sensor device 330, thus preventing thesensor device from being exposed to the high temperatures of the mold.Preferably the sensor device 330 is positioned on the exterior of themold half 14; however, in alternate embodiments, the sensor device 330may be positioned at a further remote location or within one of the moldhalves 14, 16 at a lower temperature point from the part-forming areasuch that the sensor device 330 is not damaged by the high temperatures.It is also contemplated that the sensor device 330 may be thermallyinsulated and/or have various known heat removal systems to protect thesensor device 330 and thus allow it to be positioned within the mold.

[0047] The sensor device 330 is preferably a charge coupled device (CCD)array electronic camera. However, in alternate embodiments, the sensordevice 330 may be any sensing device such as, for exemplary purposesonly, an infrared or near infrared camera or infrared heat sensor.

[0048] In the preferred embodiment, the analyzing means 340 receives anelectronic representation of the acquired image from the sensor device330, analyzes said image and communicates the presence or absence ofmolded parts within the mold 12 to the part-forming machine controller72. Given known parameters, one skilled in the art would be able todevelop software for analyzing the images of the mold 12. The analyzingmeans 340 is preferably integrated with the part-forming machinecontroller 72; however, a separate controller/computer may be utilizedthat is communicationally linked with the part-forming machinecontroller 72.

[0049] Due to the generally parallel positioning of the capture source310, as soon as the sensor device 330 receives a signal from the machinecontroller 72 that the mold is beginning to open, the first image isimmediately acquired while the mold 12 is opening, in lieu of waitingfor a signal from the machine controller 72 that the mold 12 hascompletely opened. The image is then analyzed to ensure that the part 22is present on the moving side of the mold half 16; the analyzing means340 sends a signal to the machine controller 72 to this affect. Next, afirst cycle of ejector rods 56, 58 is performed. This step can now beperformed while the mold 12 is opening. A second image is acquired andanalyzed to determine the absence of the part 22 in mold half 16,wherein if the part 22 is still present, another series of ejector rods56, 58 is performed or an alarm is activated, depending on the number ofcycles performed, to indicate to the operator that the part 22 is stuck.If the second image indicates that the part 22 is absent, the analyzingmeans 340 sends a signal to the machine controller 72 to close the mold12 and begin the next molding process.

[0050] More specifically, in the first state A illustrated in FIG. 4,the analyzing means 340 sends a mold close signal via the machinecontroller 72 or via any other data communication means to the injectionmolding machine 10. In response, a close/open mechanism that includes aram actuator actuates the ram 38 to close and press mold half 16 againstthe mold half 14 and followed by actuation of the plastic extrude system42 to inject liquid or molten plastic into the mold 12 to form a plasticpart. After allowing sufficient time for the plastic to harden, theprocess advances as indicated by arrow 76 to state B in which the ram 38is actuated to pull mold half 16 away from mold half 14. While the mold12 is opening as illustrated in state B, an image of the open mold half16 is acquired by sensor device 330 via capture source 310 andtransmitted via electrical cable 78, or any other known transmittingmeans, to the analyzing means 340, which compares the image to an idealimage of the mold half 16 as it should appear with a properly formedplastic part 22 in the cavity. This comparison function of analyzingmeans 340 is indicated in FIG. 4 by decision block 80. At this point inthe sequence, there should be a fully formed hard plastic part 22 inmold half 16. Therefore, if the comparison at decision block 80indicates that no plastic part 22 is present in mold half 16 or thatplastic part 22 is present but incompletely formed, the analyzing means340 stops the sequence and generates a signal to an alarm 82 or otherdevice as indicated by arrow 84, to signal an operator 86 to come andcheck the injection molding machine 10. However, if the comparisonindicates that a fully formed plastic part 22 is present in the moldhalf 16, as it is supposed to be, the analyzing means 340 causes thesequence to continue, as indicated by arrow 88, to state C by sending asignal via the machine controller 72 to actuate the ejector system 18 toextend the ejector rods 56, 58 to cycle once to hit or push the hardplastic part out of the mold half 16. However, as discussed above,occasionally, one extension of ejector rods 56, 58 will not dislodge orclear the hard plastic part 22 from mold half 16. Therefore, theanalyzing means 340 causes the sequence to proceed as indicated by arrow90 to state D.

[0051] In state D, the analyzing means 340 acquires another image of themold half 16 by sensor device 330 via capture source 310 and istransmitted via electrical cable 78, or any other known transmittingmeans and compares it, as indicated by decision block 92, to an idealimage, which is stored in memory, of the mold half 16 with the hardplastic part 22 removed and the mold cavity 50 (not seen in FIG. 4)empty. If the comparison at decision block 92 indicates that the part 22is cleared and the cavity 50 is empty, the analyzing means 340 continuesthe sequence as indicated by arrow 94 back to state A by sending asignal via the machine controller 72 to actuate the ram 38 to againclose the mold 12 and to actuate the extruder system 42 to again fillthe mold 12 with plastic. On the other hand, if the comparison atdecision block 92 indicates the part 22 is stuck in the mold half 16 asindicated by phantom lines 22′ or otherwise not cleared, then theanalyzing means 340 proceeds as indicated by arrow 96 to check thenumber of times that the ejector rods 56, 58 have been extended orcycled. If, as indicated at decision block 98, the ejector rods 56, 58have been cycled more than some reasonable number, such as five (5), inunsuccessful tries to dislodge and clear the part 22 from the mold half16, the analyzing means 330 stops the sequence, and, as indicated byarrow 100, proceeds to signal the alarm 82 or other device 86 to callthe operator. However, if the number of tries has not exceeded thenumber, such as five (5), the analyzing means 340 returns the sequenceto state C, as indicated by arrow 102, by signaling the ejector actuatorvia the machine controller 72 to again fire or cycle the ejector rods56, 58 to hit or push the part 22 once again. The analyzing means 340then continues the sequence again as indicated by arrow 90 to state Dwhere another image of the mold half 16 is acquired with sensor device330 and compared again at 92 to the ideal image of how the mold half 16should appear with the part cleared. If the part 22 was successfullycleared by the last extension or cycle of the ejector pins 56, 58, thesequence proceeds as indicated by arrow 94 to state A. However, if thecomparison at 92 indicates the part 22′ is still stuck or not cleared,the analyzing means 340 checks the number of tries at 98 and, if notmore than the number, e.g., five (5), returns the sequence to state Cagain. The maximum number of tries set in decision 98 can be any number,but it is preferably set at a number, for example five (5), that isdeemed to allow enough cycles or extensions of ejector rods 56, 58 toreasonably be expected to dislodge and clear the part 22 withoutbecoming practically futile. Thus, multiple cycles of extensions andretractions of the ejector rods 56, 58 are available and used when thepart 22 gets stuck, but the invention prevents unneeded repetitivecycles of the ejector rods 56, 58 when the part 22 has been dislodgedand cleared from the mold.

[0052] As previously discussed and as shown in FIG. 9, the prior-artmethod of placing the vision system on top of the mold results in askewed view as the angle of the target increases relative to the camera.Consequently, a larger view area for each pixel 400 results therebydecreasing the resolution of the image. In the present invention,however, as shown in FIG. 10, the sensor or camera is held at arelatively parallel angle with the target, and as such, the view areafor each pixel is smaller 410 and more consistent thereby resulting inan image having higher resolution. As a result, more accurate analysiscan be made with images having better resolution.

[0053] In the preferred embodiment, the sensor device 330 has anillumination source that can travel via linking means 320 to the capturesource 310 thereby directly illuminating the part 22 and/or mold 12 at asubstantially parallel angle thereto. As a result, better lighting ofthe target area is possible thus increasing the clarity and accuracy ofthe acquired image. In an alternate embodiment, it is contemplated thatthere may be a separate illumination source attached in-line with thesensor device 330 or alternatively an illumination source that isindependent therewith.

[0054] It should be noted that although the above in-mold sensor systemis described in combination with a skip-eject system, the in-mold sensorsystem may be utilized with any part-forming machine. It should also benoted that any number of sensor devices 330 and/or capture sources 310may be utilized.

[0055] Having thus described exemplary embodiments of the presentinvention, it should be noted by those skilled in the art that thewithin disclosures are exemplary only, and that various otheralternatives, adaptations, and modifications may be made within thescope of the present invention. Accordingly, the present invention isnot limited to the specific embodiments illustrated herein, but islimited only by the following claims.

What is claimed is:
 1. A machine for forming parts, comprising: a mold;means for ejecting at least one of the parts from said mold; means forcontrolling said ejecting means; at least one sensor positioned withinsaid mold, said sensor is in view of said mold at a substantiallyparallel angle therewith, wherein the parts formed by said machine areimageable by said sensor; means for analyzing the image captured by saidsensor, said analyzing means generating an indication of the presence,absence or quality of at least one of the parts, said analyzing means incommunication with said ejection means, wherein said ejection means isresponsive to said indication.
 2. The machine of claim 1, wherein saidejecting means is at least one ram.
 3. The machine of claim 1, whereinsaid means for controlling said ejecting means is a programmablecomputer.
 4. The machine of claim 1, wherein said analyzing means is aprogrammable computer.
 5. The machine of claim 1, wherein said analyzingmeans is a programmable microprocessor.
 6. The machine of claim 1,wherein said sensor is at least one charge coupled device camera.
 7. Themachine of claim 1, wherein said sensor is at least one infrared sensor.8. The machine of claim 7, wherein said infrared sensor is at least oneinfrared camera.
 9. A machine for forming parts, comprising: a moldhaving an interior and an exterior; means for ejecting at least one ofthe parts from said mold; means for controlling said ejecting means;means for capturing an image, said image capture means positioned insaid interior of said mold, said image capture means is in view of saidmold at a substantially parallel angle therewith, wherein an image ofthe parts formed by said machine are captured by said image capturemeans; a sensor device in communication with said image capture means;means for transferring the image from said image capture means to saidsensor device; means for analyzing the image captured by said sensordevice, said analyzing means in communication with said sensor device,said analyzing means generating an indication of the presence, absenceor quality of at least one of the parts, said analyzing means incommunication with said ejection means, wherein said ejection means isresponsive to said indication.
 10. The machine of claim 9, wherein saidimage capture means is at least one fiber optic bundle.
 11. The machineof claim 9, wherein said image capture means is at least one lens. 12.The machine of claim 9, wherein said ejecting means is at least one ram.13. The machine of claim 9, wherein said means for controlling saidejecting means is a programmable microprocessor.
 14. The machine ofclaim 9, wherein said analyzing means is a programmable microprocessor.15. The machine of claim 9, wherein said sensor is at least one chargecoupled device camera.
 16. The machine of claim 9, wherein said sensoris at least one infrared sensor.
 17. The machine of claim 15, whereinsaid infrared sensor is at least one infrared camera.
 18. The machine ofclaim 9, wherein said transfer means is at least one fiber optic bundle.19. A method of indicating the presence, absence and quality of a partin a part-forming machine, comprising the steps of: a. acquiring animage of the part at a relatively parallel angle thereto; b.transferring said image to an image analyzer; c. analyzing said image;and d. sending a signal to a part-forming machine controller, whereinsaid part-forming machine controller is responsive to said signal fromsaid image analyzer.
 20. The method of claim 19, wherein said step a. ofacquiring an image of the part at a relatively parallel angle thereto isperformed while the mold is opening.